Flow control valve

ABSTRACT

A flow control valve in which a part of a low pressure refrigerant passage connected to an evaporator in a refrigeration cycle is placed in a very closely spaced apart relation with a part of a high pressure refrigerant passage to the evaporator; a heat sensitive device having means for detecting the environmental temperature and means which is displaced in response to the detected temperature is so placed as to contact the temperature detecting means with refrigerant the low pressure refrigerant passage; and a flow control valve for controlling the flow in the high pressure refrigerant passage is operatively coupled to the heat sensitive member.

[ 51 Aug. 15, 1972 United States Patent Oshima et al.

[54] FLOW CONTROL VALVE 2,379,286 6/l945 Dodson.......................62/225 Inventors: Ryoichiro Oshima; SeigoMiyamoto, 2,539,062 1/1951 both of Hitachi; Kazuo Kanemoto, Katsuta;Michio Ichikawa Shimizu 3,388,864 6/1968Nozkes........................62/225 a" ofjapan 3,450,345 6/1969 Orth[73] Assignee: Hitachi, Ltd., Tokyo, Japan [22] Filed:

Primary Examiner-Meyer Perlin Attorney-Craig, Antonelli & Hill Oct. 5,1970 ABSTRACT A flow control valve in which a [21] Appl. No.: 78,145

[30] Foreign Application Priority Data refrigerant passage connected toan eva refrigeration cycle is placed in a very closely spaced Oct. 6,1969 Japan ....44/79l72 apart relation with a part of a high pressurerefrigerant passage to the evaporator; a heat sensitive device hav- B m2M0 15 W 5 M3 4 0 N. m 3, a i 2 a H m 2 2 m mh c m d mm IF ll] 8 55 [flee m w ett po e m mh eet [mum m ma twp r nS e m mm m fdd we m n mM eh]eW mmmm oPES .mh m. o 6.mufi t tc ewa d flt e Z fame m dd emwm m mp mmmpressure refrigerant passage; and a flow control valve [56] ReferencesCited for controlling the flow in the high pressure refrigerant UNITEDSTATES PATENTS passage is operatively coupled to the heat sensitivemember.

9 Claim, 6 Drawing Figures 2,520,l9l 8/1950Aughey.......................62/225 2,642,724 6/1953 Carter ....62/225Patented Aug. 15, 1972 3,683,637

4 Sheets-Sheet 1 FIG.I

INVENTORS RvouzmRo OSPJMR, SE60 MWHMO kaluo \ARNEMOTO ammo zco-umwq BYCm AM, smmk QIQQQSL ATTORNEYS Patented Aug. 15, 1972 3,683,637

4 Sheets-Sheet 2 FIG. 2

IN VENTORS A'ITL )RNIEYS Patented Aug. 15, 1972 4 Sheets-Sheet SINVENTORS Knzuo KRNEMOTO dymwo :uaumwn BY has, QM, 3W? 141m ATTORNEYSPatented Aug. 15, 1972 4 Sheets-Sheet 4 INVENTORS BY 0103 RM,W* 1mgATTORNEYS BACKGROUND OF THE INVENTION The present invention relates to aflow control device in a refrigeration cycle.

In general, the expansion valves are used as the device described. Inorder to control the flow of the refrigerant to be supplied into anevaporator, the pressure as well as temperature of the refrigerant atthe outlet of the evaporator are detected so that their deviations fromthe reference values may be exerted upon the surfaces of a diaphragm tothereby control the opening of the inlet of the evaporator by a valvewhich is actuated in response to the displacement of the diaphragm. Morespecifically, the pressure representative of the temperature of therefrigerant is applied to one surface of the diaphragm while thepressure of the refrigerant is applied to the other surface thereof sothat the valve may be actuated in response to the pressure differencebetween the two pressures. The temperature of the refrigerant may beconverted into the pressure by a remote bulb attached to the outer thediaphragm through a capillary tube. -The pressure acting upon onesurface of the diaphragm is trans mitted with a relatively long timedelay and is influence i by the ambient temperature so that the correctpressure is not transmitted to the diaphragm. Therefore, the

expansion valve cannot function properly. Especially in low pressurepipe connected to the evaporator through a header and to the lowpressure pipe itself. Thus, the interconnecting system is very complexand there arises a problem of leakage of gas from the capillary tubes.

SUMMARY OF THE INVENTION The present invention was made to overcome theproblems described above, and provides a novel flow control valve whichnot only functions as an expansion valve but also accomplishes otherfunctions to be described in more detail hereinafter.

The first object of the present invention is to provide a flow controlvalve in which the pressure variation which is representative of thevariation in temperature of the refrigerant at the outlet of anevaporator may be accurately and immediately transmitted toa diaphragmin the flow control valve.

The second object of the present invention is to provide a flow controlvalve in which the variation in pressure of the refrigerant in theevaporator may be immediately transmitted to the diaphragm so thatoptimum flow control of the refrigerant may be attained.

e The third object of the present invention is to simpliapart relationwith the outlet passage from the evaporacase of an air conditioning unitmounted in an automo-j" bile, the air flowing in contact with and invicinity of the remote bulb pulsates so that the pulsating signals aretransmitted to the diaphragm. I

0n the other hand, the pressure acting upon the other side of thediaphragm is generallythe static pressure of the refrigerant at theoutlet of the evaporator so that the suitable control may be attained inthe normal 7 operation of the air conditioning unit.

However, in case of the air conditioning unit mounted in the automobile,the variation in refrigeration load occurs especially when the airconditioner is started and when the door is opened so that the largeamount of the surrounding air flows into the compartment. Inconsequence, there occurs liquid-back phenomenon, that is the phenomenonthat the liquid refrigerant cannot vaporize in the evaporator completelyso that the liquid refrigerant is forced into the compressor.Consequently, the recovery to the optimum overheated temperature delayedso that the cooling or refrigeration capacity is accordingly lowered.Furthermore, the compressor is adversely affected because of the suddenincrease of the pressure within the compressor and noise is produced.

These problems may be overcome if the expansion valve may immediatelyreduce the flow of the refrigerant so that the suitable amount of flowmay be introduced into the evaporator in response to the capacitythereof.

The expansion valve is interconnected with the evaporator through amember connecting the outlet of the expansion valve to the evaporatorthrough the distributor and through capillary tubes for transmitting 1the pressures to the expansion valve, said capillary tubes beingconnected to a remote bulb attached to a tor; a heat sensitive bulb isplaced in the outlet passage and is made in contact with a casing of onechamber on one side of a diaphragm of an expansion valve; the totalpressure (static as well as dynamic pressures) of the refrigerant in theoutlet passage of the evaporator may be transmitted to a chamber on theother side of the diaphragm; and a valve placed in the inlet passage ofthe evaporator may be controlled in response to the displacement of thediaphragm.

The present invention will become more apparent from'the followingdesciption of the preferred embodiment thereof taken in conjunction withthe accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERREDEMBODIMENT Prior Art Referring to FIG. 1, the refrigeration cycle of theprior art air conditioner will be described in brief in order to aid theunderstanding of the present invention. A refrigerant is compressed by acompressor 1, cooled by a condenser 2 and stored in liquid phase in aliquid tank or receiver 3. The main flow control of the refrigerant toan evaporator 6 is made by an expansion valve in a high pressure pipe 4,and after the heat exchange for cooling the air in a room, therefrigerant is returned to the compressor 1 through a low pressure pipe7. The expansion valve 5 is provided with a device consisting of acapillary tube 8 and a remote bulb 9 for detecting a temperature of therefrigerant in the low pressure pipe 7 and converting it into a pressureand a capillary tube 10 for directly detecting a pressure of therefrigerant. The high pressure pipe 4 is communicated with each tube 11of the evaporator through a distributor 12 while the low pressure pipe 7is communicated with the tubes 1 1 through a header 13. The Invention Inbrief, the present invention contemplates to arrange the high and lowpressure pipes 4 and 7 in closely spaced apart relation with each otherand locate the remote bulb 9 in the low pressure pipe 4 so as toeliminate the capillary tubes 8 and 10. Furthermore, the distributor l2,header l3, expansion valve and remote bulb are made into a unitaryconstruction so that the device may be designed compact in size.

Referring to FIGS. 2 to 5, the present invention will be described. Aflow control valve generally designated by 15 comprises a valve body 16provided with an inlet passage 17, a reduced diameter passage 18 and aplurality of distributor passages 19. A heat sensitive element 20 isplaced upon the valve body 16 and enclosed by a cover 21, which issecurely fixed to the valve body 16 by means of bolts 22. Within thecover 21 are defined a distribution chamber 23 and header chamber 24.The heat sensitive element 20 comprises a partition plate 27 and adiaphragm 28 both of which are secured in position between a lowercasing 26 and an upper casing 25. The lower casing 26 is retained on thevalve body 16. CO gas as well as activated carbon are enclosed in achamber 29 defined between the upper casing 25 and the partition plate27. In a chamber 31 defined between the partition plate 27 and thediaphragm 28 is filled with CO gas. The upper and lower chambers 29 and31 are intercommunicated with each other through passages 32. A valverod 34 has one end fixed to a ball valve 35, with the other end being incontact with a spacer 33. The spacer 33 consists of a thin platedisposed between the diaphragm 28 and the valve rod 34 to protect saiddiaphragm 28. The ball valve 35 is received by a valve seat 36 and aspring 38 is interposed between the valve seat 37 and an adjustmentscrew 37. A chamber 39 defined between the diaphragm 28 and a lowercasing 26 is intercommunicated with the header chamber 24 throughpassages 40. The distribution chamber 23 has a plurality of distributionpipes 41 connected thereto and the pipes 41 are the inlets of the tubesin the evaporator 6. The outlets of the tubes of the evaporator 6 whichare the header pipes 42 are communicated with the header chamber 24. Theinlet passage 17 is communicated with the liquid tank through the highpressure pipe. A low pressure pipe 44 from the header chamber 24 isconnected to the suction port of the compressor. Reference numeral 45designates a tube for sealing the gas. Reference numeral 46 designatessealing members and the distribution and header chambers 23 and 24 aresealed from each other by a sealing member 46.

The flow control of the refrigerant entering into the inlet passage 17is made by the ball valve 35 and the refrigerant is forced into thedistribution chamber 23 through the reduced diameter passage 18 and thento the evaporator 6 through the distribution pipes 41. The refrigerantfrom the evaporator 6 flows into the header chamber 24 through theheader pipes 42 and then into the compressor through the low pressurepipe 44.

In this case, the degree of opening of the ball valve 35 is determinedby the downwardly acting force of the diaphragm 28 of the heat sensitiveelement 20 and the reaction force of the spring 38. The downwardlyacting force is produced by the difference in pressure acting upon theupper surface and undersurface of the diaphragm. The pressure exertingupon the upper surface of the diaphragm 28 is a function of atemperature of the refrigerant in the header chamber 24 while thepressure exerting upon the undersurface of the diaphragm 28 is the sumof the static and dynamic pressures of the refrigerant in the headerchamber 24 transmitted through the passages 40.

In the present invention, CO gas 29 can be replaced by other gas, suchas Freon or the like which is sensitive to the variation of thetemperature. In this case, activated carbon 30 and the partition plate27 are eliminated as shown in FIG. 6.

In the prior art system, the expansion valve is communicated with theremote bulb through the capillary tubes as described above. However, inaccordance with the present invention, the diaphragm chamber in theexpansion chamber is directly made in contact with the heat sensitivecylinder, that is the heat sensitive element 20, so that there is anadvantage that the variation in output pressure in response to thevariation in detected temperature may be accurately and immediatelytransmitted to the diaphragm.

Since the header pipes 42 are angularly displaced from the low pressurepipe 44 so that the refrigerant is forced to change its flow in theheader chamber 24. In consequence, the whole pressure of the refrigerantmay be directly transmitted to the chamber 39.

The diaphragm in the flow control valve of the present invention may bedisplaced precisely in response to the variation in pressure andtemperature of the refrigerant in the low pressure passage.

In the prior art expansion valve, there is a long time interval from thetime the variation in pressure and temperature of the refrigerant in thelow pressure passage occurs to the time the diaphragm is displacedaccordingly. That is, a response time is very long. How ever, theresponse of the flow control valve in accordance with the presentinvention is very fast. This means, the flow of the refrigerant may bequickly controlled in response to the operating conditions of the airconditioner or the variation in load. Therefore, the pulsations ofvarious physical quantities which tend to occur in response to theactuation of a suction throttle valve of the conventional type may beeliminated.

Furthermore, the cool-down capacity of quickly cooling the roomtemperature to a desired level after the air conditioner is started ismuch improved. The flow into the evaporator of the refrigerant may be socontrolled that the liquid back may be minimized.

What is claimed is:

1. A flow control valve comprising; a valve body, an inlet passageformed in one end of said valve body, a

plurality of distribution passages formed in the side of the valve bodyso as to communicate with said inlet passage, valve means disposedbetween the inlet passage and the distribution passages, a heatsensitive device retained on the valve body on the side opposite theportion where said inlet passage is formed, said heat sensitive devicehaving an output member operative upon sensing the temperature andpressure of surrounding refrigerant, means for operatively connectingthe output member of said heat sensitive device to said valve means, acup-shaped cover fixed to said valve body with the sides of heatsensitive device and said valve body located inside thereof, adistribution chamber formed between the valve body and the cover, aheader chamber formed between the heat sensitive device and the cover,sealing means for sealingly separating said distribution and headerchambers from one another, distribution means for communicating each ofthe inlet ends of a plurality of tubes of an evaporator directly withthe distribution chamber, header means for communicating each of theoutlet ends of a plurality of the tubes of the evaporator directly withthe header chamber, said cover being supported at said distributionchamber and header chamber such that the portion of said cover formingthe outer surface of said header chamber is closely spaced from theevaporator, means for connecting a low pressure refrigerant passage of arefrigeration cycle with the header chamber, and means for connecting ahigh pressure refrigerant passage of a refrigeration cycle to the inletpassage of the valve body.

2. A flow control valve as defined in claim 1, wherein said heatsensitive device is composed of a partition wall and a diaphragminterposed between upper and lower casings, integrally secured to eachother at their outer edges, said lower casing being retained directly onthe valve body, said upper casing and said partition wall defining afirst chamber therebetween, said partition wall and said diaphragmdefining a second chamber therebetween, said diaphragm and said lowercasing and said valve body defining a third chamber therebetween, saidfirst and second chambers being communicated with each other throughpassage means, said first chamber being charged with gas and anadsorbent, said second chamber being charged with the same gas as insaid first chamber, and said third chamber being communicated with theheader chamber through a passage.

3. A flow control valve as defined in claim 1, wherein said heatsensitive device is composed of a diaphragm interposed between an uppercasing and a lower casing integrally secured to each other at theirouter edges, said lower casing being retained directly on the valvebody, said upper casing and said diaphragm defining a first chambertherebetween, said diaphragm and said lower casing defining a secondchamber therebetween, said first chamber having gas sealed therein andsaid second chamber being communicated with the header chamber through apassage.

4, A flow control valve as defined in claim 1, wherein said valve meansincludes a ball valve provided in the inlet passage and a spring urgingsaid ball valve into a closed position, a valve rod being axiallyslidably disposed within the valve body with one end thereof conn ted tosaid valv b l, and a s a er bein interpose between one end of the valveIP08 and un ersurface of the output member of the heat sensitive device.

5. A flow control valve arrangement for a refrigerating cycle of thetype having a plurality of evaporator tubes running parallely through anevaporator; said arrangement comprising: housing means, inlet means insaid housing means for introducing refrigerant from a high pressurerefrigerant source, a distributing chamber in communication with saidinlet means by way of inlet valve means, a plurality of distributorchamber outlet means for communicating between said distributor chamberand respective inlets to a plurality of evaporator tubes, a headerchamber in direct communication with all of the respective outlets ofsaid plurality of evaporator tubes for collecting all the low pressurerefrigerant after it passes through the evaporator, a sensing devicearranged in said header chamber for sensing pressure and temperaturecharacteristics of the low pressure refrigerant in said header chamber,and control means operatively connecting said sensing device to theinlet valve means for controlling the flow of refrigerant into thedistrubition chamber as a function of the temperature and pressurecharacteristics of the refrigerant in said header chamber, said headerchamber and said distribution chamber being arranged in said housingmeans and being separated from one another by common partition means.

6. An arrangement according to claim 5, characterized in that saidcontrol means includes a rigid control rod extending through said commonpartition means.

7. An arrangement according to claim 5, characterized in that saidhousing means is constructed as a cylindrically shaped rigid housing,said inlet means including an inlet passage at one end of the housing,said distribution chamber outlet means comprising a first set ofpassages extending radially outward through the side walls of thehousing, and the communication between the header chamber and theoutlets of said evaporator tubes being by way of a second set ofpassages extending radially outward through the side walls of thehousing.

8. An arrangement according to claim 7, characterized in that saidhousing is supported with respect to the remaining refrigerating cycleby the connection between the evaporation tubes and the first and secondset of passages.

9. An arrangement according to claim 7, characterized in that saidhousing includes a one-piece cylindrical cup shaped cover detachablyattached to a valve body at the edges of the open end of the cover, saidfirst and second sets of passages extending through the side walls ofsaid cover. I

1. A flow control valve comprising; a valve body, an inlet passageformed in one end of said valve body, a plurality of distributionpassages formed in the side of the valve body so as to communicate withsaid inlet passage, valve means disposed between the inlet passage andthe distribution passages, a heat sensitive device retained on the valvebody on the side opposite the portion where said inlet passage isformed, said heat sensitive device having an output member operativeupon sensing the temperature and pressure of surrounding refrigerant,means for operatively connecting the output member of said heatsensitive device to said valve means, a cup-shaped cover fixed to saidvalve body with the sides of heat sensitive device and said valve bodylocated inside thereof, a distribution chamber formed between the valvebody and the cover, a header chamber formed between the heat sensitivedevice and the cover, sealing means for sealingly separating saiddistribution and header chambers from one another, distribution meansfor communicating each of the inlet ends of a plurality of tubes of anevaporator directly with the distribution chamber, header means forcommunicating each of the outlet ends of a plurality of the tubes of theevaporator directly with the header chamber, said cover being supportedat said distribution chamber and header chamber such that the portion ofsaid cover forming the outer surface of said header chamber is closelyspaced from the evaporator, means for connecting a low pressurerefrigerant passage of a refrigeration cycle with the heAder chamber,and means for connecting a high pressure refrigerant passage of arefrigeration cycle to the inlet passage of the valve body.
 2. A flowcontrol valve as defined in claim 1, wherein said heat sensitive deviceis composed of a partition wall and a diaphragm interposed between upperand lower casings, integrally secured to each other at their outeredges, said lower casing being retained directly on the valve body, saidupper casing and said partition wall defining a first chambertherebetween, said partition wall and said diaphragm defining a secondchamber therebetween, said diaphragm and said lower casing and saidvalve body defining a third chamber therebetween, said first and secondchambers being communicated with each other through passage means, saidfirst chamber being charged with gas and an adsorbent, said secondchamber being charged with the same gas as in said first chamber, andsaid third chamber being communicated with the header chamber through apassage.
 3. A flow control valve as defined in claim 1, wherein saidheat sensitive device is composed of a diaphragm interposed between anupper casing and a lower casing integrally secured to each other attheir outer edges, said lower casing being retained directly on thevalve body, said upper casing and said diaphragm defining a firstchamber therebetween, said diaphragm and said lower casing defining asecond chamber therebetween, said first chamber having gas sealedtherein and said second chamber being communicated with the headerchamber through a passage.
 4. A flow control valve as defined in claim1, wherein said valve means includes a ball valve provided in the inletpassage and a spring urging said ball valve into a closed position, avalve rod being axially slidably disposed within the valve body with oneend thereof connected to said valve ball, and a spacer being interposedbetween one end of the valve rod and undersurface of the output memberof the heat sensitive device.
 5. A flow control valve arrangement for arefrigerating cycle of the type having a plurality of evaporator tubesrunning parallely through an evaporator; said arrangement comprising:housing means, inlet means in said housing means for introducingrefrigerant from a high pressure refrigerant source, a distributingchamber in communication with said inlet means by way of inlet valvemeans, a plurality of distributor chamber outlet means for communicatingbetween said distributor chamber and respective inlets to a plurality ofevaporator tubes, a header chamber in direct communication with all ofthe respective outlets of said plurality of evaporator tubes forcollecting all the low pressure refrigerant after it passes through theevaporator, a sensing device arranged in said header chamber for sensingpressure and temperature characteristics of the low pressure refrigerantin said header chamber, and control means operatively connecting saidsensing device to the inlet valve means for controlling the flow ofrefrigerant into the distrubition chamber as a function of thetemperature and pressure characteristics of the refrigerant in saidheader chamber, said header chamber and said distribution chamber beingarranged in said housing means and being separated from one another bycommon partition means.
 6. An arrangement according to claim 5,characterized in that said control means includes a rigid control rodextending through said common partition means.
 7. An arrangementaccording to claim 5, characterized in that said housing means isconstructed as a cylindrically shaped rigid housing, said inlet meansincluding an inlet passage at one end of the housing, said distributionchamber outlet means comprising a first set of passages extendingradially outward through the side walls of the housing, and thecommunication between the header chamber and the outlets of saidevaporator tubes being by way of a second set of passages extendingradially outward through the side walls of the housing.
 8. Anarrangement acCording to claim 7, characterized in that said housing issupported with respect to the remaining refrigerating cycle by theconnection between the evaporation tubes and the first and second set ofpassages.
 9. An arrangement according to claim 7, characterized in thatsaid housing includes a one-piece cylindrical cup shaped coverdetachably attached to a valve body at the edges of the open end of thecover, said first and second sets of passages extending through the sidewalls of said cover.